1. Field of the Invention
The present invention relates to a braking force regulating structure for a braking device, and more particularly to a braking assembly with a manageable self-generating power energy.
2. Description of the Prior Art
A conventional braking assembly, such as the brake for an exercise bike, mainly includes a rotor and a stator. Two corresponding curved braking plates are pivotally connected to the stator, and a plurality of curved permanent magnets are provided at an outer circumferential surface of the curved braking plates, such that outer circumferentially surfaces of the curved permanent magnets face toward an inner circumferential surface of the rotor with a proper air clearance left between them. When the rotor rotates, an eddy current is produced as a result of an induction between the permanent magnets and the rotor and consequently, a dragging force will be applied the rotor. The smaller the air clearance between the permanent magnets and the rotor is, the stronger the induced eddy current is, and the larger the produced dragging/braking force is. Accordingly, this dragging force can be used as the resistance of sporting equipment.
To regulate the braking force, the conventional braking assembly includes a cable that can be manually operated to pull one of two ends of each curved braking plate and thereby adjust a distance of the air clearance between the outer circumferential surfaces of the permanent magnets and the inner circumferential surface of the rotor and accordingly, the braking force of the braking assembly.
Other similar types of conventional braking structures are also found in prior patents. U.S. Pat. No. 6,360,855 discloses a brake for an exercise bike. The brake includes a first and a second disc-shaped plate, a center shaft extended between the two disc-shaped plates, and a plurality of bars and rollers located between the two disc-shaped plates to space the latter from each other by a predetermined distance. The brake also internally includes two curved plates having magnets provided on outer circumferential surfaces thereof. The two curved plates are pivotally connected at an end to and between the two disc-shaped plates, and connected at the other end to a pulling cord. When the pulling cord is pulled, a braking effect of the brake may be changed.
A disadvantage of the above-mentioned conventional brakes is that it must be manually operated to regulate the braking force thereof. To change the manually operated brake to a power-controlled brake, it is necessary to connect with an external power source so as to supply power to a driving mechanism of the brake. This requirement restricts the mounting of the brake to a position close to a power supply, otherwise wiring to power source is needed.
Therefore, it is desired to release the conventional brake from the limitations of being mounted close to the external power source, so that the brake may be conveniently used at any place.
To meet the above requirement, there is developed a self-excitation type power-generating braking structure. U.S. Pat. No. 6,084,325 discloses a brake device with a combination of power-generating and eddy-current magnetic resistance, in which a power-generating coil is provided to one side of a flywheel. When the flywheel rotates, the power-generating coil is caused to generate electrical energy to produce a braking force. However, the power-generating coil must work with the large flywheel to produce the required electrical energy and could not be integrated into the braking device. This results in a complicate structure of the braking device and troublesome assembling and mounting thereof.
It is therefore tried by the inventor to develop a braking assembly with self-generating power energy to eliminate the drawbacks existed in the conventional brakes.